S835
Clinical - Lung
ESTRO 2026
2020;142:217-223. 2. Eriguchi T et al. Systematic Review and Meta-Analysis. Cancers (Basel).MDPI. 2022;14(15). 3. Khadige M, et al. Cyberknife SRT for stage i lung cancer and pulmonary metastases. J Thorac Dis. 2018;10(8):4976-4984. 4. Janvary ZL et al. Clinical outcomes of 130 patients with Cyberknife SBRT. Radiol Oncol. 2017;51(2):178-186. 5. Davis JN et al. SBRT for centrally located ES NSCLC. RSSearch® patient registry. Radiation Oncology. 2015;10(1). 6. Owen D, Siva S, Salama JK, Daly M, Kruser TJ, Giuliani M. Some Like It Hot: Int Jour of Rad Onc*Biology*Physics. 2023;117(1):1-5. Keywords: lung SBRT, BED10, real-world data, LC, BED10 Digital Poster 4182 Thoracic Re-Irradiation: An 8-year safety review to inform modern practice Gemma Wheeler, Denise Berehoudougou, Ciaran Malone, Colin Kelly, Pierre Thirion Radiation Oncology, St. Luke’s Radiation Oncology Network, Dublin, Ireland Purpose/Objective: The growing number of long-term cancer survivors has led to an increase in patients at risk of relapse or secondary malignancies. Consequently, repeat courses of radiotherapy are becoming more frequent, supported by advances in planning and delivery. Despite the expanding clinical adoption of re- irradiation, there remains a lack of robust data on patient demographics, indications, and radiotherapy technical modality including dose volume constraints (DVCs) . Moreover, considerable heterogeneity in re- irradiation practice limits the ability to ensure safety, reproducibility, and efficacy. The aim is to present and
record available were included in the LC analysis. Results: A total of 190 targets and 129 patients were analysed. Median GTV and PTV volumes (among available) were 8.3 cm ³ [0.1-48.4] and 26.6 cm ³ [3.1-117.3], respectively (outliers excluded). Median prescribed BED ₁₀ was 151.2 Gy [IQR 115.5-151.2]. The median Dmean(PTV) was 128.2 Gy [IQR 103.5-136.2] and Dmean(GTV) was 149.5Gy [IQR 114.7-150.8] (Figure 1). FU data were available for 138 FU imaging data were available for 137 lesions with a median FU of 13.6 months [1.4-82.6]. Observed LC rates (Kaplan-Meier, Figure 2) were 89% at 1 year, 82% at 2 years, and 73% at 4 years (mixed primary/metastatic cohort), that comparable to a similar mixed population3–5, but slightly lower than NSCLC-only cohorts6.
evaluate a standardised, technology-agnostic approach for radical thorax radiotherapy or
stereotactic ablative body radiotherapy (SABR) for thoracic re-irradiation including fixed cumulative DVCs developed institutionally used consistently over the past eight years. Material/Methods:
Conclusion: In this single-institution analysis with GTV-based prescription in lung SBRT, Dmean(GTV) closely matched the nominal prescription, suggesting tumour level dose consistency. The Ray-Tracing - Monte Carlo workflow is appropriate for heterogeneous lung environment and supports the feasibility of GTV- centred prescription in clinical practice. Local-control rates were comparable to published series when biological dose was similar. More rigorous cross-study comparison remains limited due to differences in heterogeneity corrections, prescription/normalisation conventions, and case mix variety. References: 1. de Jong E, Guckenberger M et al. Variation in current prescription practice of.. the ACROP guideline and ICRU report 91. Radiotherapy and Oncology.
All institutional re-irradiations for Lung thorax/SABR thorax from 2017-2025 were screened. Cases were included if type I re-irradiation was present, defined as direct geometric overlap between prior and current treatments confirmed by physician review on the planning CT. A standard three-step workflow was
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